Phenotypic Characterization of Immortalized Chondrocytes from a Desbuquois Dysplasia Type 1 Mouse Model: A Tool for Studying Defects in Glycosaminoglycan Biosynthesis.

The complexity of skeletal pathologies makes use of in vivo models essential to elucidate the pathogenesis of the diseases; nevertheless, chondrocyte and osteoblast cell lines provide relevant information on the underlying disease mechanisms. Due to the limitations of primary chondrocytes, immortalized cells represent a unique tool to overcome this problem since they grow very easily for several passages. However, in the immortalization procedure the cells might lose the original phenotype; thus, these cell lines should be deeply characterized before their use. We immortalized primary chondrocytes from a Cant1 knock-out mouse, an animal model of Desbuquois dysplasia type 1, with a plasmid expressing the SV40 large and small T antigen. This cell line, based on morphological and biochemical parameters, showed preservation of the chondrocyte phenotype. In addition reduced proteoglycan synthesis and oversulfation of glycosaminoglycan chains were demonstrated, as already observed in primary chondrocytes from the Cant1 knock-out mouse. In conclusion, immortalized Cant1 knock-out chondrocytes maintained the disease phenotype observed in primary cells validating the in vitro model and providing an additional tool to further study the proteoglycan biosynthesis defect. The same approach might be extended to other cartilage disorders.

A Stepwise Algorithmic Approach and External Validation Study for Noninvasive Prediction of Advanced Fibrosis in Nonalcoholic Fatty Liver Disease.

BACKGROUND AND AIMS: Advanced F3-4 fibrosis predicts liver-related mortality in nonalcoholic fatty liver disease (NAFLD). Noninvasive tests, designed to rule in/out advanced fibrosis, are limited by indeterminates, necessitating biopsy. We aimed to determine whether stepwise combinations of noninvasive serum-based tests and elastography (VCTE) could predict F3-4, reduce indeterminates, and decrease liver biopsies. METHODS AND RESULTS: Five hundred forty-one biopsy-proven NAFLD cases were identified between 2010 and 2018 from two Canadian centers. Characteristics of training (n = 407)/validation (n = 134) cohorts included: males 54%/59%; mean age 48.5/52.5 years; mean body mass index 32.3/33.6 kg/m2; diabetes mellitus 30%/34%; and F3-4 48%/43%. For training/validation cohorts, area under the receiver operating curve (AUROC) for FIB-4, AST-platelet ratio index (APRI), NAFLD fibrosis score (NFS), BARD score, and AST/ALT ratio ranged from 0.70 to 0.83/0.68 to 0.81, with indeterminates 25-39%/34-45%, for F3-4. In the training cohort, parallel FIB-4 + NFS had good accuracy (AUROC = 0.81) but was limited by 38% indeterminates and 16% misclassified. Sequential FIB-4 → NFS reduced indeterminates to 10%, and FIB-4 → VCTE to 0%, misclassified 20-22%, while maintaining high specificity (0.88-0.92) and accuracy (AUROC 0.75-0.78) for combined cohorts. Liver biopsy could have been avoided in 27-29% of patients using sequential algorithms. CONCLUSIONS: Sequential FIB-4 âž” NFS/VCTE predicts F3-4 with high specificity and good accuracy, while reducing indeterminates and need for biopsy. Parallel algorithms are limited by high indeterminates. Sequential FIB-4 âž” NFS had similar accuracy to VCTE-containing algorithms. Validation in low-prevalence cohorts may allow for potential use in community or resource-limited areas for risk stratification.

Ellis van Creveld: reporte de caso / Ellis van Creveld: Case report

Introduction: Ellis-van Creveld (EVC) (OMIM # 225500) syndrome is a rare skeletal dysplasia disorder transmitted by autosomal recessive inheritance. The diagnosis is made based on phenotypic characteristics such as chondrodysplasia, heart defects and polydactyly. The prognosis depends mainly on the severity of the disease, diagnosis and comprehensive management of the condition. Objective: To describe a patient diagnosed with EVC syndrome. Case report: Newborn diagnosed with EVC syndrome who presented dysmorphic facies, shortened long bones, rhizomelic shortening, small hands, brachydactyly, single transverse palmar crease, postaxial polydactyly in the upper limbs, bilateral preaxial polysyndactyly in lower limbs and hypoplastic nails, complex heart defects and narrow thorax. The evolution was unfavorable; the patient died 8 weeks after birth from complications due to heart defects. Conclusions: EVC syndrome is rare and unknown; therefore, it is important to spread its characteristics within the pediatric community, emphasizing that it affects multiple organ systems and requires a multidisciplinary approach to treat individually each patient, to provide genetic and reproductive counseling to couples and to give information regarding child development expectations.

Introducción: El síndrome Ellis-van Creveld (EVC) (OMIM #225500) es una displasia esquelética rara de herencia autosómica recesiva, cuyo diagnóstico se realiza por sus características fenotípicas como la condrodisplasia, cardiopatía y polidactilia. El pronóstico depende fundamentalmente de la severidad de la cardiopatía, al igual que del diagnóstico y manejo integral oportunos. Objetivo: Caracterizar un paciente con diagnóstico clínico de Síndrome de EVC, cuya baja frecuencia dificulta el correcto diagnóstico en pediatría. Caso clínico: Recién nacido con facies dismórfica, extremidades con huesos largos cortos, acortamiento rizomélico, manos pequeñas, braquidactilia, pliegue palmar único, polidactilia post axial en miembros superiores, polisin-dactilia preaxial bilateral en miembros inferiores y uñas hipoplásicas, cardiopatía compleja y tórax estrecho, en el que se concluyó un diagnóstico clínico de EVC. La evolución fue desfavorable, falleciendo a las 8 semanas de nacimiento por complicaciones secundarias a la cardiopatía. Conclusiones: El síndrome de EVC es de baja frecuencia y poco conocido, por lo que es importante difundir sus características en la comunidad pediátrica, haciendo énfasis en que al afectar múltiples sistemas y órganos, requiere un manejo multidisciplinario con el objetivo de intervenir en la patología individualizando cada paciente; además de consejería genética y reproductiva a las parejas, e información de las expectativas del desarrollo del niño.

Vascular limb defects and maternal age.

BACKGROUND: The prenatal diagnosis procedure chorionic villus sampling is associated with increased risk of vascular disruption limb defects. Some studies have suggested that these defects are more common among infants born to women 35 years and older while other studies have shown a correlation with younger mothers. METHODS: All infants with vascular disruption defects were identified in the Active Malformations Surveillance Program at Brigham and Women's Hospital in the years 1972-1974, 1979-2011. We compared the rate of occurrence of infants with vascular limb defects among women in theses age groups: ≤19, 20 to 34, and ≥35 years to the rate of occurrence of infants with preaxial polydactyly, adjusting for race. Infants with an identifiable cause of their defects were excluded. RESULTS: 106 infants with vascular disruption defects and 67 with preaxial polydactyly were identified. Seventeen percent of the infants with vascular disruption defects and 25% of the infants with preaxial polydactyly were born to women 35 and older (p = 0.23). In contrast, 16% of the infants with vascular disruption defects were born to young mothers (≤19 years) compared with 6.0% of the mothers of infants with preaxial polydactyly (adjusted odds ratio vs. 35+ years = 5.3, 95% confidence interval 1.4-21, p = 0.017). CONCLUSION: Women 35 years old or older did not have increased risk for having a child with vascular disruption defects, but these defects were more common among infants of young (≤19) mothers, compared with the preaxial polydactyly group.

[Ellis van Creveld. Case report]. / Ellis van Creveld: reporte de caso.

INTRODUCTION: Ellis-van Creveld (EVC) (OMIM # 225500) syndrome is a rare skeletal dysplasia disorder transmitted by autosomal recessive inheritance. The diagnosis is made based on phenotypic characteristics such as chondrodysplasia, heart defects and polydactyly. The prognosis depends mainly on the severity of the disease, diagnosis and comprehensive management of the condition. OBJECTIVE: To describe a patient diagnosed with EVC syndrome. CASE REPORT: Newborn diagnosed with EVC syndrome who presented dysmorphic facies, shortened long bones, rhizomelic shortening, small hands, brachydactyly, single transverse palmar crease, postaxial polydactyly in the upper limbs, bilateral preaxial polysyndactyly in lower limbs and hypoplastic nails, complex heart defects and narrow thorax. The evolution was unfavorable; the patient died 8 weeks after birth from complications due to heart defects. CONCLUSIONS: EVC syndrome is rare and unknown; therefore, it is important to spread its characteristics within the pediatric community, emphasizing that it affects multiple organ systems and requires a multidisciplinary approach to treat individually each patient, to provide genetic and reproductive counseling to couples and to give information regarding child development expectations.

Effects of electromagnetic pulse on polydactyly of mouse fetuses.

There is an increasing public concern regarding potential health impacts from electromagnetic radiation exposure. Embryonic development is sensitive to the external environment, and limb development is vital for life quality. To determine the effects of electromagnetic pulse (EMP) on polydactyly of mouse fetuses, pregnant mice were sham-exposed or exposed to EMP (400 kV/m with 400 pulses) from Days 7 to 10 of pregnancy (Day 0 = day of detection of vaginal plug). As a positive control, mice were treated with 5-bromodeoxyuridine on Days 9 and 10. On Days 11 or 18, the fetuses were isolated. Compared with the sham-exposed group, the group exposed to EMP had increased rates of polydactyly fetuses (5.1% vs. 0.6%, P < 0.05) and abnormal gene expression (22.2% vs. 2.8%, P < 0.05). Ectopic expression of Fgf4 was detected in the apical ectodermal ridge, whereas overexpression and ectopic expression of Shh were detected in the zone of polarizing activity of limbs in the EMP-exposed group and in the positive control group. However, expression of Gli3 decreased in mesenchyme cells in those two groups. The percentages of programmed cell death of limbs in EMP-exposed and positive control group were decreased (3.57% and 2.94%, respectively, P < 0.05, compared with 7.76% in sham-exposed group). In conclusion, polydactyly induced by EMP was accompanied by abnormal expression of the above-mentioned genes and decreased percentage of programmed cell death during limb development.

Diagnóstico clínico y molecular de síndrome de cefalopolisindactilia de Greig. A propósito de un caso. / Clinical and molecular cephalopolysyndactyly Greig syndrome. A case report

El síndrome de cefalopolisindactilia de Greig (SCPG) es una afección autosómica dominante caracterizada por polidactilia o sindactilia de manos y pies, macrocefalia, hipertelorismo y ocasionalmente anomalías cerebrales y retraso mental. Es un síndrome poco frecuente, heredado según un patrón autosómico dominante. La prevalencia es ignorada, siendo conocidos 100 casos aproximadamente. Más del 75 % de los pacientes con manifestaciones clínicas características de SCPG presentan mutaciones en el gen GLI3. El diagnóstico presuntivo de SCPG puede realizarse cuando el paciente presenta la tríada clásicade polidactilia, hipertelorismo y macrocefalia, siendo indicativo para la realización del análisis molecular del gen GLI3. En este trabajo se describe el caso de un niño referido al Instituto de Genética Médica con diagnóstico clínico de polidactilia y macrocefalia. Las características clínico-evolutivas e imagenológicas del paciente permitieron postular el diagnóstico de SCPG. El análisis molecular del gen GLI3 confirmó el diagnóstico de SCPG identificando la mutación c.1850_1852 del GTTinsAT (p.R617LfsX11) en el exón 12 del gen GLI3. Se trata de una mutación no descrita previamente como una mutación asociada al desarrollo de SCPG; no obstante, al tratarse de una mutación que provoca una proteína truncada desde el exón 12 del gen GLI3, no existen muchas dudas sobre su patogenicidad. Este resultado tiene implicaciones hereditarias y familiares permitiendo un adecuado asesoramiento genético en el contexto familiar.

Congenital panfollicular nevus associated with polydactyly.

A 2-year-old girl presented with ulnar-sided duplication of the left thumb distal to the interphalangeal joint and syndactyly of the first web space. She also had several asymptomatic pink-tan cutaneous papules, involving the first and second ray of the left hand and wrist, clinically resembling a linear epidermal nevus. Microscopically, the papules were composed of well-circumscribed aggregates of basaloid epithelium within the dermis. No normal hair follicles were identified. Follicular germ and papillae were identified, representing abortive attempts at hair follicle formation. The features were remarkably similar to a novel entity described by Finn and Argenyi as congenital panfollicular nevus. In our case, the congenital panfollicular nevus was associated with distal thumb polysyndactyly, which may suggest an important link between limb patterning and hair follicle development.

Poland syndrome (anomaly) with congenital hemangioma: a new association.

Unilateral defect of pectoral muscle and ipsilateral syndactyly constitute Poland syndrome. Absence or hypoplasia of the breast and nipple, axillary hair loss and dermatoglyphic abnormalities have also been reported in this syndrome. The primary defect could be in the development of the proximal subclavian artery with early deficit of blood flow to the distal limb and the pectoral region, resulting in partial loss of tissue in those regions. However, the association of congenital hemangioma with Poland sequence has not been observed so far. Such an association is being reported here in a 1-year-old infant, second-born of nonconsanguineous parents, who also had polydactyly instead of the documented syndactyly.

[Thumb duplication: an analysis of 72 thumbs]. / Cift basparmak anomalisi: 72 olgunun degerlendirilmesi.

OBJECTIVES: The aim of this study was to evaluate patients who were operated on for a duplicated thumb. METHODS: Sixty-seven patients (41 females, 26 males; mean age 2.5 years; range 6 months to 20 years) underwent surgery for a total of 72 duplicated thumbs between 1982 and 2003. Five patients had bilateral involvement. The anomaly was on the right in 39 cases, and on the left in 33 cases. Clinical and radiographic evaluations were made according to the Wassel classification. The Bilhaut-Cloquet technique was used in 13 symmetrically duplicated thumbs, while simple excision of the unserviceable part was performed in the remaining. Patient satisfaction was assessed with the use of a visual analog scale after a mean follow-up period of 3.6 years (range 1 to 10 years). RESULTS: Nail deformity was present in all cases treated by the Bilhaut-Cloquet technique. These thumbs did not exhibit growth retardation, but interphalangeal joint motion was limited in five, while seven had a larger size compared to the normal side. Limited range of motion was detected in eight cases (11.9%), affecting the metacarpophalangeal joint in one, and the interphalangeal joint in the others. Seventeen patients (25.4%) developed an angulation of more than 10 degrees in the alignment of the thumb. Secondary procedures were necessary in 25 cases (37.3%), including collateral ligament reconstruction (n=12; 17.9%), tendon rerouting (n=3; 4.5%), corrective osteotomy (n=5; 7.5%), and arthrodesis of the interphalangeal joint (n=5; 7.5%). Patient satisfaction with the surgical outcome was 85% (n=57). CONCLUSION: It is important to evaluate and treat the skin, nail, bone, and the ligaments in a simultaneous manner in order to obtain a good reconstruction and to decrease both the complications and the need for subsequent operations.

An acylatable residue of Hedgehog is differentially required in Drosophila and mouse limb development.

The Drosophila Hedgehog protein and its vertebrate counterpart Sonic hedgehog are required for a wide variety of patterning events throughout development. Hedgehog proteins are secreted from cells and undergo autocatalytic cleavage and cholesterol modification to produce a mature signaling domain. This domain of Sonic hedgehog has recently been shown to acquire an N-terminal acyl group in cell culture. We have investigated the in vivo role that such acylation might play in appendage patterning in mouse and Drosophila; in both species Hedgehog proteins define a posterior domain of the limb or wing. A mutant form of Sonic hedgehog that cannot undergo acylation retains significant ability to repattern the mouse limb. However, the corresponding mutation in Drosophila Hedgehog renders it inactive in vivo, although it is normally processed. Furthermore, overexpression of the mutant form has dominant negative effects on Hedgehog signaling. These data suggest that the importance of the N-terminal cysteine of mature Hedgehog in patterning appendages differs between species.

Visual loss as the presenting sign of Jeune syndrome.

We describe a 5-year-old girl with Jeune syndrome. The presenting symptoms included visual loss and night blindness only. In the neonatal period she had surgery on both hands for bilateral polydactyly. Following clinical and radiological examination a diagnosis of Jeune syndrome was proposed. Although Jeune syndrome is often characterized by multiple organ abnormalities, our patient presented with ocular symptoms at the age of 5 years.

Clinical and genetic studies on 12 preaxial polydactyly families and refinement of the localisation of the gene responsible to a 1.9 cM region on chromosome 7q36.

Polydactyly is the most frequently observed congenital hand malformation with a prevalence between 5 and 19 per 10000 live births. It can occur as an isolated disorder, in association with other hand/foot malformations, or as a part of a syndrome, and is usually inherited as an autosomal dominant trait. According to its anatomical location, polydactyly can be generally subdivided into pre- and postaxial forms. Recently, a gene responsible for preaxial polydactyly types II and III, as well as complex polysyndactyly, has been localised to chromosome 7q36. In order to facilitate the search for the underlying genetic defect, we ascertained 12 additional families of different ethnic origin affected with preaxial polydactyly. Eleven of the kindreds investigated could be linked to chromosome 7q36, enabling us to refine the critical region for the preaxial polydactyly gene to a region of 1.9 cM. Our findings also indicate that radial and tibial dysplasia/aplasia can be associated with preaxial polydactyly on chromosome 7q36. Combining our results with other studies suggests that all non-syndromic preaxial polydactylies associated with triphalangism of the thumb are caused by a single genetic locus, but that there is genetic heterogeneity for preaxial polydactyly associated with duplications of biphalangeal thumbs. Comparison of the phenotypic and genetic findings of different forms of preaxial polydactyly is an important step in analysing and understanding the aetiology and pathogenesis of these limb malformations.